[3.16.y-ckt stable] Patch "x86/reboot: Add ASRock Q1900DC-ITX mainboard reboot quirk" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    x86/reboot: Add ASRock Q1900DC-ITX mainboard reboot quirk

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt10.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 77f6f3baee5ee799c5f312d56b53361a57dad9f6 Mon Sep 17 00:00:00 2001
From: Stefan Lippers-Hollmann <s.l-h at gmx.de>
Date: Mon, 30 Mar 2015 22:44:27 +0200
Subject: x86/reboot: Add ASRock Q1900DC-ITX mainboard reboot quirk

commit 80313b3078fcd2ca51970880d90757f05879a193 upstream.

The ASRock Q1900DC-ITX mainboard (Baytrail-D) hangs randomly in
both BIOS and UEFI mode while rebooting unless reboot=pci is
used. Add a quirk to reboot via the pci method.

The problem is very intermittent and hard to debug, it might succeed
rebooting just fine 40 times in a row - but fails half a dozen times
the next day. It seems to be slightly less common in BIOS CSM mode
than native UEFI (with the CSM disabled), but it does happen in either
mode. Since I've started testing this patch in late january, rebooting
has been 100% reliable.

Most of the time it already hangs during POST, but occasionally it
might even make it through the bootloader and the kernel might even
start booting, but then hangs before the mode switch. The same symptoms
occur with grub-efi, gummiboot and grub-pc, just as well as (at least)
kernel 3.16-3.19 and 4.0-rc6 (I haven't tried older kernels than 3.16).
Upgrading to the most current mainboard firmware of the ASRock
Q1900DC-ITX, version 1.20, does not improve the situation.

( Searching the web seems to suggest that other Bay Trail-D mainboards
  might be affected as well. )
--
Signed-off-by: Stefan Lippers-Hollmann <s.l-h at gmx.de>
Cc: Matt Fleming <matt.fleming at intel.com>
Link: http://lkml.kernel.org/r/20150330224427.0fb58e42@mir
Signed-off-by: Ingo Molnar <mingo at kernel.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 arch/x86/kernel/reboot.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
index 52b1157c53eb..f319bfea154e 100644
--- a/arch/x86/kernel/reboot.c
+++ b/arch/x86/kernel/reboot.c
@@ -181,6 +181,16 @@ static struct dmi_system_id __initdata reboot_dmi_table[] = {
 		},
 	},

+	/* ASRock */
+	{	/* Handle problems with rebooting on ASRock Q1900DC-ITX */
+		.callback = set_pci_reboot,
+		.ident = "ASRock Q1900DC-ITX",
+		.matches = {
+			DMI_MATCH(DMI_BOARD_VENDOR, "ASRock"),
+			DMI_MATCH(DMI_BOARD_NAME, "Q1900DC-ITX"),
+		},
+	},
+
 	/* ASUS */
 	{	/* Handle problems with rebooting on ASUS P4S800 */
 		.callback = set_bios_reboot,